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BUG: KCSAN: data-race in kick_pool_pick / wq_worker_running

read-write to 0xffff888237c2b0a4 of 4 bytes by task 3661 on cpu 0:
 wq_worker_running+0x9c/0x120 kernel/workqueue.c:1465
 io_schedule+0x3e/0x60 kernel/sched/core.c:8220
 folio_wait_bit_common+0x3db/0x660 mm/filemap.c:1329
 folio_wait_bit+0x25/0x30 mm/filemap.c:1473
 folio_wait_writeback+0x59/0x120 mm/page-writeback.c:3062
 __filemap_fdatawait_range mm/filemap.c:532 [inline]
 file_write_and_wait_range+0x23b/0x2f0 mm/filemap.c:789
 ext4_sync_file+0x114/0x5c0 fs/ext4/fsync.c:145
 vfs_fsync_range fs/sync.c:186 [inline]
 vfs_fsync+0xbe/0xd0 fs/sync.c:200
 aio_fsync_work+0x76/0x100 fs/aio.c:1698
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0x56a/0xa50 kernel/workqueue.c:3479
 worker_thread+0x569/0x750 kernel/workqueue.c:3560
 kthread+0x223/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff888237c2b0a4 of 4 bytes by task 3654 on cpu 1:
 need_more_worker kernel/workqueue.c:954 [inline]
 kick_pool_pick+0x5f/0x310 kernel/workqueue.c:1284
 __queue_work+0x90a/0xbc0 kernel/workqueue.c:2449
 queue_work_on kernel/workqueue.c:2501 [inline]
 schedule_work_on include/linux/workqueue.h:742 [inline]
 schedule_on_each_cpu+0x1af/0x340 kernel/workqueue.c:4774
 vmstat_refresh+0x20/0x2a0 mm/vmstat.c:2015
 proc_sys_call_handler+0x2ec/0x4a0 fs/proc/proc_sysctl.c:600
 proc_sys_read+0x1f/0x30 fs/proc/proc_sysctl.c:621
 new_sync_read fs/read_write.c:493 [inline]
 vfs_read+0x699/0x7c0 fs/read_write.c:574
 ksys_pread64 fs/read_write.c:764 [inline]
 __do_sys_pread64 fs/read_write.c:772 [inline]
 __se_sys_pread64 fs/read_write.c:769 [inline]
 __x64_sys_pread64+0xfd/0x150 fs/read_write.c:769
 x64_sys_call+0xd2e/0x2550 arch/x86/include/generated/asm/syscalls_64.h:18
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3654 Comm: syz-executor391 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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